Concentration count per mass Amount of substance or a count/number of items per unit mass. This is most often called molality or molal concentration. This contrasts with the definition of molarity which is based on a specified volume of solution. A commonly used unit for molality used in chemistry is mol/kg. A solution of concentration 1 mol/kg is also sometimes denoted as 1 molal. Chemistry QUDT http://qudt.org/vocab/quantity#AmountOfSubstancePerUnitMass; http://dbpedia.org/page/Molality ODM2 Units Type Controlled Vocabulary ODM2 Working Group A vocabulary for describing the type of the Unit or the more general quantity that the Unit represents.